Migrant Raptors along the Rift

More than 50% of migratory raptors in the African-Eurasian region have a poor conservation status, and many species of birds of prey are in decline. According to the Convention on Migratory Species, the most significant reasons include changes in land use practices (which lower the availability of prey), loss of breeding grounds, climate-driven habitat change, pollution, poisoning, collisions with power lines, and hunting and persecution. (While some birds of prey have been highly valued as hunting partners, other raptors, especially the largest, have suffered from persecution by people who feared them, or who resented their perceived or actual predation of livestock and game.)

Raptors have low rates of reproduction and, as predators at the top of the food chain, tend to be naturally scarce, which increases their vulnerability to threats.

Indicators of Ecosystem Health

Given their position at the top of the food chain, raptors are indicators of ecosystem health. Because they typically require significant areas of habitat, conservation measures to benefit birds of prey enable an umbrella of protection for entire ecological communities.

“Bottlenecks”

Raptors use thermals for their long journeys, and avoid flying over large bodies of water. Hundreds of thousands of individuals can be seen at “bottlenecks” along established routes of passage that minimize the extent of water crossings. One example is in southern Israel, over Eilat, where about 1.2 million migrating raptors are counted each spring. Israel is a major crossroads for palearctic migrants: 43 species of migrant raptors pass over Israel as they journey along Great Rift Valley flyway into Africa, including Lesser Kestrels (Falco naumanni), Lesser Spotted Eagles (Aquila pomarina), and Steppe Eagles (Aquila nipalensis)

The Lesser Kestrel (Falco naumanni) breeds from the Mediterranean across southern central Asia to China, and winters in Africa and Pakistan. This species is classified as “Vulnerable” because, according to the IUCN, it has suffered drastic declines – in western Europe, equivalent to roughly 46% in each decade since 1950; and on its wintering grounds in South Africa, equal to about 25% in each decade since 1971; and possibly in parts of its Asian range as well. Similar declines are predicted to continue over the next decade.

The Lesser Spotted Eagle (Aquila pomarina) breeds in Central and Eastern Europe. Satellite-tracked birds of this species were found to cover an average of 166 km per day during migration to Africa and back – a total of 19,400 km. Outward and return migrations each took about 7.5 weeks. (Meyburg, Scheller, & Meyburg)

The Steppe Eagle (Aquila nipalensis) breeds from Romania through southeastern Russia and Central Asia to Mongolia and Manchuria in eastern China (Meyburg 1994). The European and Central Asian birds winter in Africa – each year more than 100,000 individuals make the journey to East Africa and as far as southern Africa and back.